New London — Construction is expected to begin this year on the largest and most complicated phase of a long-delayed $108 million project to reconstruct and expand New London High School.

Work at the so-called north campus, which eventually will be home to three magnet schools, could start as early as May if the current timeline holds. It is the first of a two-part, nearly $160 million overall public magnet school project that also involves an overhaul of Bennie Dover Jackson Middle School.

A team of school and city officials led by a project manager from the Capitol Region Education Council spent two days in meetings last week poring over construction documents with representatives from the state Department of Administrative Service’s Division of School Construction and Review.

The expected outcome, said CREC’s Senior Project Manager Diana McNeil, is an approval from the state that allows the city to move forward and put the north campus project out to bid. A letter of approval is expected to come within the next week.

A shovel in the ground for the “renovate as new” project would be a major milestone for a project whose funding — a total of $168 million — was first approved by voters in 2014. The state is reimbursing the city 80 percent of the costs of most of the project and 95 percent of a $10 million portion added last year.

Work on the north campus technically began on a running track rehab project and continued last year with hazmat cleanup, but McNeil said the upcoming work is the real heart of the work and a “big deal.”

The project will increase the footprint of the new facility, which includes the adjacent Science and Technology High School of Southeastern Connecticut, from 173,900 square feet to 290,765 square feet. The project timeline puts the completion date in the fall of 2023.

The newer STEM Magnet High School, which opened in 2006, will remain virtually untouched during construction.

Construction will continue while classes are in session over the next several years. McNeil said it complicates the project but plans are in place to mitigate as much as possible the disruptions to students.

There is no swing space to move students off campus, so the work will include construction of walls to block off portions of the building. McNeil said an addition will be one of the first projects, a move that will create more space to move students into while construction crews tackle older parts of the school.

Three entities contracted by the city for the work include architectural firm Antinozzi Associates; Newfield + Downes, the construction manager; and CREC, which oversees the entire project.

Bryan Doughty, a member of the Board of Education and School Building and Maintenance Committee, who has at times expressed frustration over the slow progress of the north campus project, said the progression to this stage is good news. “It’s exciting. We’re further along than we’ve ever been in the process,” he said. “It’s been a struggle. I just want to make sure the project continues to move along.”

Plans and programing for the two schools have changed dramatically over the years and had at one point included a $31 million downtown arts campus at the Garde Arts Center.

Planning was underway for two sixth- through 12th-grade schools and four magnet pathways when the state issued a directive in 2018 — a year after construction was planned to start — that eliminated one of the pathways. The schools will now have three: science, technology, engineering and math, or STEM; international studies, and arts. The district is seeking to have an International Baccalaureate program as part of its international studies magnet pathway.

The sixth- through 12th-grade model also changed to a plan that more closely resembles a typical middle school and high school. The exception is the arts pathway, which will be completely contained at the north campus.

It was only after the state settled on the specs for the schools that McNeil said the project team was able to start the final design. All other designs to that point mostly were scrapped and McNeil said the new design was completed in 14 months, a feat for a project of this size.

“We’ve had some serious changes on the project,” he said, referring to the school design as a “moving target.”

g.smith@theday.com